1. Field of the Invention
The present invention relates generally to molten metal processing and specifically to an apparatus and method for automatically centering a metering pin in the pouring spout of a molten metal pouring pot.
2. Description of the Prior Art
Spouts for pouring molten metal are well known in the prior art. Examples of such spouts are disclosed in U.S. Pat. Nos. 3,628,706, 3,673,039, 3,752,372 and 3,805,877. Several methods of controlling flow of molten metal during pouring are also known in the prior art. U.S. Pat. No. 3,182,360 illustrates a method of valve control external of the pouring pot. U.S. Pat. No. 3,384,150 illustrates a pouring method operated by gas pressure. U.S. Pat. Nos. 3,746,072 and 3,903,954 disclose methods of pouring molten metal with a unique spout purged of air and U.S. Pat. No. 4,098,321 teaches pouring molten metal at a constant flow rate by maintaining the molten metal pressure depth. Metering pin type molten metal control devices are also very well known in the prior art. U.S. Pat. No. 2,615,216 illustrates a yielding nozzle which conforms to a plug. U.S. Pat. No. 3,331,539 discloses a metering device which has long service life because direct exposure to heat is limited only to the metering pin. U.S. Pat. No. 3,422,881 illustrates a conventional metering rod within a spout which comprises a continuous casting belt. U.S. Pat. No. 3,452,808 illustrates another conventional metering rod within an adjustable spout and U.S. Pat. No. 3,528,479 shows a metering pin controlled by a gamma radiation device. Additionally, U.S. Pat. No. 3,958,730 illustrates a four part stopper rod plug assembly which is claimed to always have complete shut off capability regardless of any warping of the components thereof.
Although numerous advances have been made in methods of pouring metal and particularly in the use of metering pins to control molten metal flow, there is no accurate method in the prior art of initially centering the metering pin in the spout of the pour pot. The prior art method of centering is by trial and error which results in excessive down time and inaccuracy which in turn often results in vortices, undesired turbulence, imprecise flow and molten metal spills.